Comal and Hays Counties, Texas
The most common soil here is Comfort, on about 20% of the land: a very stony clay, sticky when wet and rock-hard when dry. Brackett and Rumple come next.
About 92% of the land drains well.
USDA rates 96% of the land very limited for a standard septic drain field, and 96% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 79% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Comal and Hays Counties, Texas, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Comal and Hays Counties, Texas. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Comfort-Rock outcrop complex, 1 to 8 percent slopes | 154K | Well drained | D | Very limited | Very limited |
| Brackett-Rock outcrop-Comfort complex, 1 to 8 percent slopes | 110K | Well drained | D | Very limited | Very limited |
| Rumple-Comfort, rubbly association, 1 to 8 percent slopes | 106K | Well drained | D | Very limited | Very limited |
| Brackett-Rock outcrop-Real complex, 8 to 30 percent slopes | 105K | Well drained | D | Very limited | Very limited |
| Real-Comfort-Doss complex, 1 to 8 percent slopes | 44K | Well drained | D | Very limited | Very limited |
| Eckrant-Rock outcrop association, 8 to 30 percent slopes | 33K | Well drained | D | Very limited | Very limited |
| Houston Black clay, 1 to 3 percent slopes | 20K | Moderately well drained | D | Very limited | Very limited |
| Bolar clay loam, 1 to 3 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Doss silty clay, moist, 1 to 5 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Heiden clay, 3 to 5 percent slopes, eroded | 16K | Well drained | D | Very limited | Very limited |
| Branyon clay, 0 to 1 percent slopes | 13K | Moderately well drained | D | Very limited | Very limited |
| Krum clay, 1 to 3 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Water | 12K | D | Not rated | Not rated | |
| Denton silty clay, 1 to 3 percent slopes | 11K | Well drained | D | Very limited | Very limited |
| Sunev clay loam, 1 to 3 percent slopes | 9K | Well drained | B | Not limited | Somewhat limited |
| Lewisville silty clay, 1 to 3 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Real gravelly loam, 1 to 8 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Purves clay, 1 to 5 percent slopes | 8K | Well drained | D | Very limited | Very limited |
| Heiden clay, 1 to 3 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Tinn clay, 0 to 1 percent slopes, frequently flooded | 7K | Moderately well drained | D | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 96% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 96% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.